Autism Spectrum Disorder (ASD) is a complex neurological disorder that typically appears before the age of 3 and immediately and profoundly affects a young child's ability to communicate, develop language, form social relationships and respond appropriately to environmental cues. Whereas all children with developmental disabilities receive some form of federally mandated Early Intervention, demands are being placed on parents and early intervention staff to provide what has been referred to as behavioral intervention (BI). Bl is a consensus "best practice" scientific treatment methodology derived from the field of Applied Behavior Analysis, that focuses on providing rigorous and sustained one-to-one and natural-context treatment to teach developmental skills such as attending, imitation, receptive language, expressive language, preacademic social and self-help skills. After being endorsed by several states, the Surgeon General of the United States and professional organizations such as the American Psychological Association, American Association on Mental Retardation, American Academy of Pediatrics, National Research Council, and the American Psychiatric Association, demand for BI providers has grown beyond what university and ASD service organizations can now provide. As a means of increasing the availability of BI training resources, Praxis, Inc., a small health care softw.are development company that specializes in programs for children with developmental disabilities, in partnership with the Eunice Kennedy Shriver Center at the University of Massachusetts Medical School, proposes to develop, implement, and evaluate web-based distance learning modules for teaching relevant BI practitioner skills. The project has three major objectives: (1) to develop curriculum materials that can be used for web-based instruction, (2) to develop a commercially viable software prototype, and (3) to evaluate the resulting program to determine the usability of the software and the effectiveness of the curriculum in teaching requisite competencies.